Urine stem cells used to create teeth

Stem cells obtained from urine could allow us to regrow lost teeth, according to scientists.

In mice, a new system of tissue culture has allowed researchers to grow the cells into tiny structures resembling teeth, and they hope one day the technology could permit them to build the real thing in human patients.

The stem cells are generated from urine, based on previous studies which have shown discarded cells in human waste can be coaxed into becoming pluripotent stem cells (iPSCs).

These can then themselves generate many different cell types, including neurons and heart muscle cells.

But researchers had yet to generate solid organs or tissues from iPSCs – until now, reported Cell Regeneration Journal.

Dr Duanqing Pei, of the Chinese Academy of Sciences, created the tooth-like structures by forcing iPSCs to mimic two different cell types; epithelial cells, which give rise to enamel, and mesenchymal cells, which give rise to the other three main components of teeth (dentin, cementum and pulp).

They first created flat sheets of epithelial cells which they then mixed with mouse embryonic mesenchymal cells.

The product was transplanted into mice, and three weeks later, tooth-like structures had grown.

The authors said: “The primitive teeth-like organs are structurally and physically similar to human teeth.

“They are of roughly the same elasticity, and contain pulp, dentin and enamel-forming cells.

“But the method has its limitations – it involves mouse cells, has a success rate of around 30% and the structures were about one-third of the hardness of human teeth.”

Tweaking the mixture of cells and the condition of the culture tissue could solve these problems, the researchers said.

They explained: “The revised method could, in theory, be used to create a bioengineered tooth bud that could be cultured in vitro then transplanted into the jawbone of a needy patient to form a fully functional tooth.” …